Foldable ladder
US4723631A · kind A · utility
Inventor
Key dates
| Filing date | Sep 17, 1986 |
| Grant date | Feb 9, 1988 |
| Priority date | — |
| Expiry date | Sep 17, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE06C1/387
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A ladder made of a rectangular main frame, spaced parallel rods interconnecting the two long side legs of the ladder, and step panels each pivotally mounted at its front corners to one rod for pivotal action within the ladder frame. A rigid link pivotally interconnects the rear corners of the step panels on each side thereof. Short lever arms also pivotally interconnect the rear portion of the side edges of the topmost step panel to the interior face of the respective side legs. Each short lever arm has a central longitudinal slot slidingly engaged by a pivot pin projecting from the frame side legs. Thus, lengthwise displacement of the link moves the step panels in between a horizontal operative position, in which the pivot pin abuts against the outer edge of the lever arm longitudinal slot farthest from the topmost step panel, and a ladder-storage position in which all elements of the ladder are coplanar with its quadrangular frame and the pivot pin abuts against the inner edge of the lever arm longitudinal slot nearest from the topmost step panel. An inverse U-shaped frame may be hinged to the main frame upper portion to constitute a stepladder and is coplanar with the main frame…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.